For various reasons it has heretofore been difficult to bond rubber to plastic and particularly to fluoroplastic. Prior art bonding systems often require special surface treatments and involve the use of expensive compounds such as epoxies, and any bonding which does occur is generally weak or decreases rapidly upon ageing. Adhesive bonds to fluoroplastics are also severely tested due to the often hostile and/or corrosive environments in which fluoroplastics are commonly used. U.S. Pat. No. 4,115,614 deals with the bonding of chlorinated polyethylenes to rubber. There is no mention of bonding fluoroplastic to rubber.
Regarding rubber to metal adhesion, there is a great deal of art in the field of tire manufacture, where such bonds are used to adhere metal belts to the rubber carcass. For the most part, adhesion promoters are used which are compounded into the rubber recipe. They are usually proprietary and expensive and further can be used only in conjunction with brass or brass coated steel.
By contrast, the instant invention provides for a relatively inexpensive, simple adhesion system which, when used to bond a fluoroplastic to rubber can withstand severe environmental conditions. The very same system can also be used to bond rubber to a metal, yet does not require special compounding or a brass coating over the metal.